It has been demonstrated that focused ultrasound directed at neural structures can stimulate those structures. If neural activity is increased or excited, the neural structure is said to be up regulated; if neural activated is decreased or inhibited, the neural structure is said to be down regulated. Neural structures are usually assembled in circuits. For example, nuclei and tracts connecting them make up a circuit. The potential application of ultrasonic therapy of deep-brain structures has been suggested previously (Gavrilov L R, Tsirulnikov E M, and I A Davies, “Application of focused ultrasound for the stimulation of neural structures,” Ultrasound Med Biol. 1996;22(2):179-92. and S. J. Norton, “Can ultrasound be used to stimulate nerve tissue?,” BioMedical Engineering OnLine 2003, 2:6). Norton notes that while Transcranial Magnetic Stimulation (TMS) can be applied within the head with greater intensity, the gradients developed with ultrasound are comparable to those with TMS. It was also noted that monophasic ultrasound pulses are more effective than biphasic ones. Instead of using ultrasonic stimulation alone, Norton applied a strong DC magnetic field as well and describes the mechanism as that given that the tissue to be stimulated is conductive that particle motion induced by an ultrasonic wave will induce an electric current density generated by Lorentz forces.
The effect of ultrasound is at least two fold. First, increasing temperature will increase neural activity. An increase up to 42 degrees C. (say in the range of 39 to 42 degrees C.) locally for short time periods will increase neural activity in a way that one can do so repeatedly and be safe. One needs to make sure that the temperature does not rise about 50 degrees C. or tissue will be destroyed (e.g., 56 degrees C. for one second). This is the objective of another use of therapeutic application of ultrasound, ablation, to permanently destroy tissue (e.g., for the treatment of cancer). An example is the ExAblate device from InSightec in Haifa, Israel. The second mechanism is mechanical perturbation. An explanation for this has been provided by Tyler et al. from Arizona State University (Tyler, W. J., Y. Tufail, M. Finsterwald, M. L. Tauchmann, E. J. Olsen, C. Majestic, “Remote excitation of neuronal circuits using low-intensity, low-frequency ultrasound,” PLoS One 3(10): e3511, doi:10.137/1/journal.pone.0003511, 2008)) where voltage gating of sodium channels in neural membranes was demonstrated. Pulsed ultrasound was found to cause mechanical opening of the sodium channels, which resulted in the generation of action potentials. Their stimulation is described as Low Intensity Low Frequency Ultrasound (LILFU). They used bursts of ultrasound at frequencies between 0.44 and 0.67 MHz, lower than the frequencies used in imaging. Their device delivered 23 milliwatts per square centimeter of brain—a fraction of the roughly 180 mW/cm2 upper limit established by the U.S. Food and Drug Administration (FDA) for womb-scanning sonograms; thus such devices should be safe to use on patients. Ultrasound impact to open calcium channels has also been suggested.
Alternative mechanisms for the effects of ultrasound may be discovered as well. In fact, multiple mechanisms may come into play, but, in any case, this would not effect this invention.
Approaches to date of delivering focused ultrasound vary. Bystritsky (U.S. Pat. No. 7,283,861, Oct. 16, 2007) provides for focused ultrasound pulses (FUP) produced by multiple ultrasound transducers (said preferably to number in the range of 300 to 1000) arranged in a cap place over the skull to effect a multi-beam output. These transducers are coordinated by a computer and used in conjunction with an imaging system, preferable an fMRI (functional Magnetic Resonance Imaging), but possibly a PET (Positive Emission Tomography) or V-EEG (Video-Electroencephalography) device. The user interacts with the computer to direct the FUP to the desired point in the brain, sees where the stimulation actually occurred by viewing the imaging result, and thus adjusts the position of the FUP according. The position of focus is obtained by adjusting the phases and amplitudes of the ultrasound transducers (Clement and Hynynen, “A non-invasive method for focusing ultrasound through the human skull,” Phys. Med. Biol. 47 (2002) 1219-1236). The imaging also illustrates the functional connectivity of the target and surrounding neural structures. The focus is described as two or more centimeters deep and 0.5 to 1000 mm in diameter or preferably in the range of 2-12 cm deep and 0.5-2 mm in diameter. Either a single FUP or multiple FUPs are described as being able to be applied to either one or multiple live neuronal circuits. It is noted that differences in FUP phase, frequency, and amplitude produce different neural effects. Low frequencies (defined as below 300 Hz.) are inhibitory. High frequencies (defined as being in the range of 500 Hz to 5 MHz) are excitatory and activate neural circuits. This works whether the target is gray or white matter. Repeated sessions result in long-term effects. The cap and transducers to be employed are preferably made of non-ferrous material to reduce image distortion in fMRI imaging. It was noted that if after treatment the reactivity as judged with fMRI of the patient with a given condition becomes more like that of a normal patient, this may be indicative of treatment effectiveness. The FUP is to be applied 1 ms to 1 s before or after the imaging. In addition a CT (Computed Tomography) scan can be run to gauge the bone density and structure of the skull.
An alternative approach is described by Deisseroth and Schneider (U.S. patent application Ser. No. 12/263,026 published as US 2009/0112133 A1, Apr. 30, 2009) in which modification of neural transmission patterns between neural structures and/or regions is described using ultrasound (including use of a curved transducer and a lens) or RF. The impact of Long-Term Potentiation (LTP) and Long-Term Depression (LTD) for durable effects is emphasized. It is noted that ultrasound produces stimulation by both thermal and mechanical impacts. The use of ionizing radiation also appears in the claims.
Adequate penetration of ultrasound through the skull has been demonstrated (Hynynen, K. and F A Jolesz, “Demonstration of potential noninvasive ultrasound brain therapy through an intact skull,” Ultrasound Med Biol, 1998 Feb;24(2):275-83 and Clement G T, Hynynen K (2002) A non-invasive method for focusing ultrasound through the human skull. Phys Med Biol 47: 1219-1236.). Ultrasound can be focused to 0.5 to 2 mm as TMS to 1 cm at best.
Komisaruk, Whipple, and their colleagues have provided significant information about the correlation between orgasm and imaging for both women and men using vaginal-cervical mechanical self-stimulation (CSS) or imagining in intact women and in other areas where there has been spinal cord injury (Komisaruk B. R. and B. Whipple, “Functional MRI of the brain during orgasm in women,” Annu Rev Sex Res., 16:62-86, 2005 and Komisaruk, B. R., Whipple, B., Crawford, A., Grimes, S., Liu, W.-C., Kalnin, A, and K. Mosier, “Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the Vagus nerves,” Brain Research 1024 (2004) 77-88, 2004). There is not much difference between the sexual responses of men's and women's brains.
In both women and me, the brain regions that activated (as judged by PET or fMRI scanning) are:
1. Cingulate Gyms (pain circuit)
2. Insula (pain circuit)
3. Amygdala (regulates emotions)
4. Nucleus Accumbens (controls dopamine release)
5. Ventral Tegmental Area (VTA) (actually releases the dopamine)
6. Hippocampus (memory)
7. Cerebellum (controls muscle function)
8. Paraventricular Nucleus of the Hypothalamus and Pituitary Gland (beta-endorphin release (decreases pain), oxytocin release (increases feelings of trust), and vasopressin (increases bonding)
In women there is activation of the Periaqueductal Gray (PAG) (controlling the “flight or fight” response). The Amygdala and Hippocampus (which deal with fear and anxiety) show decreased activity—perhaps because women have more of a need to feel safe and relaxed in order to enjoy sex. In both women and men, the Left Lateral Orbitofrontal Cortex and the Temporal Lobes shut down during orgasm.
Sexually related sensory signals come from the vagina, cervix, clitoris, and uterus in women. In terms of transmission through nerve distribution:
1. Hypogastric Nerve (uterus and the cervix in women; prostate in men)
2. Pelvic Nerve (vagina and cervix in women; rectum in both sexes)
3. Pudendal Nerve (clitoris in women; scrotum and penis in men)
4. Vagus Nerve (cervix, uterus and vagina (true whether or not the spinal cord is intact)
Women can also have orgasms from stimulation of many parts of their bodies are stimulated (e.g., mouth, the nipples, the anus, hand). In women and men with spinal cord injuries, orgasms have been described when skin is stimulated around the level of the injury because of the heightened sensitivity there. Women can have orgasms without touching their body through imagery alone.
A peripheral Orgasmatron is known in that in 2004 Dr. Stuart Meloy, an anesthesiologist and pain expert in Winston-Salem, N.C., reported that sacral nerve stimulation with an implanted electrode resulted in an orgasm in ten of eleven women being treated for other conditions (Meloy, T. S. & Southern, J. P. “Neurally Augmented Sexual Function in Human Females: A Preliminary Investigation,” Neuromodulation Volume 9, No. 1 (2006): 34-40).
It would be desirable to apply ultrasound neuromodulation to the treatment of anorgasmia, hypo-orgasmia, and for the production of orgasms (Orgasmatron).